While bariatric surgery is effective in achieving long-term weight loss in morbidly obese subjects, we have found a high prevalence of post-operative esophageal disease associated with deleterious effects of weight reduction, nutritional status, and gastrointestinal symptoms. We propose to study a cohort of patients undergoing roux-en-Y gastric bypass. Baseline esophageal function will be studied with a symptom questionnaire, EMS and EGD. Eating pattern will be identified. Post-operative follow-up at 8 weeks and 1 year will repeat these studies and correlate changes in esophageal function to post-operative patterns of eating and weight loss.